Oxidation Numbers of Chromium and Oxygen

This video tutorial explains the concept of oxidation numbers, focusing on chromium. It begins by discussing the oxidation number of chromium in its neutral state and as a free element. The tutorial then demonstrates how to calculate the oxidation numbers for chromium in compounds like Cr2O3 and CrCl2, highlighting the role of oxygen and chlorine in these calculations. The video concludes with examples of different oxidation states chromium can exhibit when bonded to various elements.

What is the oxidation number of a free element like chromium (Cr) when it is not bonded to any other element?

• +1

• 0

• +2

• -1

In the compound Cr2O3, what is the oxidation number of oxygen?

• +3

• -2

• -1

• +2

How do the oxidation numbers of chromium and oxygen balance out in Cr2O3?

• Chromium +3, Oxygen -2

• Chromium +2, Oxygen -1

• Chromium +1, Oxygen -3

• Chromium +6, Oxygen -2

In CrCl2, what is the oxidation number of chlorine?

• +1

• +2

• -1

• -2

What is the oxidation number of chromium in CrCl2?

• +6

• +1

• +2

• +3

In the compound Cr2O3, what is the total oxidation number contributed by the oxygen atoms?

• -6

• +6

• -3

• +3

What is the oxidation number of chromium in Cr2O3?

• +6

• +4

• +3

• +2

Which of the following is a possible oxidation state for chromium when bonded to different elements?

• +1

• +2

• +4

• +5

What is the oxidation number of chromium when it is bonded to oxygen in a compound?

• +1

• +2

• +3

• +6

When chromium is in a compound with oxygen, what is the typical oxidation number of oxygen?

• -1

• -2

• +1

• 0